diff --git a/.changeset/sour-trains-argue.md b/.changeset/sour-trains-argue.md
new file mode 100644
index 000000000..d23b8e032
--- /dev/null
+++ b/.changeset/sour-trains-argue.md
@@ -0,0 +1,5 @@
+---
+"sst": patch
+---
+
+SvelteKitSite: Handle different basePath formats
diff --git a/packages/sst/src/constructs/SvelteKitSite.ts b/packages/sst/src/constructs/SvelteKitSite.ts
index 4301ba14e..9344a244b 100644
--- a/packages/sst/src/constructs/SvelteKitSite.ts
+++ b/packages/sst/src/constructs/SvelteKitSite.ts
@@ -159,8 +159,8 @@ export class SvelteKitSite extends SsrSite {
               pattern: fs
                 .statSync(path.join(sitePath, clientDir, item))
                 .isDirectory()
-                ? `${basePath}${item}/*`
-                : `${basePath}${item}`,
+                ? path.join(basePath, item, "*")
+                : path.join(basePath, item),
               origin: "s3",
             } as const)
         ),